Carbureting system



Filed March 21, 1957 April 14,1959

--c. R. LUNN CARBURETING SYSTEM 2 Sheets-Shes?. 1

IN VEN TOR.

April 14, 1959 C, R, LUNN 2,881,746

CARBURETI'NG SYSTEM v Filed March 21. 1957 2 Sheets-Sheet INVENTOR.

ATTORNEY United States Patent O 'CARBURETING SYSTEM Clarence R. Lunn, Lathrup Village, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application March 21, 1957, Serial No. 647,697

4 Claims. (Cl. 123-127) The present invention relates to a carbureting system for an internal combustion engine in which a plurality of carburetors are compounded in a way to provide economical fuel consumption during normal driving operation as well as high power performance when such demand is made by the operator.

In this system a primary or manually controlled carburetor is coupled with one or more additional carburetors in such a way that the primary carburetor is adapted to supply the combustible mixture under all except high power conditions. Further, this system is arranged such that the primary carburetor controls means for power actuating the auxiliary carburetor or carburetors. The present case is an improvement of copending application Serial No. 620,099, Burrell, tiled November 2, 1956, and provides a simplified engine temperature responsive means for rendering the auxiliary carburetor or carburetors inoperative regardless of primary carburetor operation until such time as the engine reaches a given operating temperature.

In the present device the improved thermostatic carburetor lockout device is disposed in the engine cooling system so that the auxiliary throttles cannot be utilized until the engine coolant has reached a given operating temperature. By so arranging thetemperature responsive means the previously employed thermostatic latching linkage, which operated from the primary carburetor automatic choke mechanism, is eliminated and with it the tendency such linkage manifested toward malfunctionmg.

In the present system, as with its predecessor, the auxiliary throttles are actuated by a vacuum servo which is supplied with a source of substantially constant value vacuum through a primary carburetor controlled air.

switch. The present device includes a temperature responsive valve disposed in the engine cooling system and which valve, when the engine temperature is below a given value, blocks the tlow of vacuum from the vacuum source to the servo.

The details of the present invention and other advantages and objects will be apparent from a perusal of the detailed description which follows.

In the drawing:

Figure l is a partly diagrammatic representation of the subject carbureting system in relation to the engine cooling system;

Figure 2 is an enlarged sectional View of the thermostatically controlled vacuum valve;

Figure 3 is an elevational View of Figure l;

Figure 4 is a fragmentary elevational View taken from Figure 1 showing the throttle actuating mechanism for one of the auxiliary carburetors; and

Figure 5 is an enlarged detail view of the throttle controlled air switch.

'Ihe present carbureting system, except for the thermostatic mechanism controlling the auxiliary throttles, is structurally and functionally the same as in the aforelACe noted copending Burrell application. Accordingly, the carbureting system will be described only to the extent necessary to place the improved thermostatic control mechanism in the proper environment.

The carbureting system includes the primary or manually controlled carburetor 10 and the auxiliary or power actuated carburetors 12 and 14. The primary carburetor includes a throttle valve 16 controlled by a lever 18 which is adapted to be suitably articulated to an accelerator controlled linkage not shown. The auxiliary carburetors I2 and 14 likewise respectively include throttle valves 20 and 22 which are coupled together through levers 24 and 26 and a connecting link 28. The throttle levers 24 and 26 have spring members 30 and 32 connected thereto, the other ends of which are anchored upon the carburetor casings so as to continuously urge the throttles toward a closed position. Through this mechanism the auxiliary throttles 20 and 22 will be operated in unison.

The actual operation of the auxiliary throttles is through a servo device 34 which is connected through a lever 36 and a link 38 to a lever 40 xed to the throttle shaft 42 of auxiliary carburetor 12. Levers 40 and 24 being fixed upon the same throttle shaft rotate together and, as described, cause the auxiliary carburetor throttle 22 to operate therewith.

Servo 34 is adapted to be supplied through conduits 44, 46 and 48 with a source of constant value vacuum from a vacuum pump indicated generally at 50. Thus, whenever vacuum is admitted to servo 34 the servo will overcome the force of throttle closing springs 30 and 32 and move'the auxiliary throttles to a wide open position. As described in the aforenoted copending application, there is no modulation of the auxiliary throttles, that is to say,

the auxiliary throttles are either completely closed or completely opened depending on the absence or presence of vacuum in the servo 34.

The ow of vacuum to the servo device is under the control of an air switch 52 which includes a slidablev member 54 adapted to either communicate the servo 34 y to atmospherethrough conduit 56 or to vacuum conduits 46 and 48 depending generally on the positionof the throttle of the primary carburetor 10. The slidable air switch vmember 54 is connected to the primary throttle f actuating lever` 18 through a link 58 and an intermediate lever 60. The linkage controlling the movable airf switch member 54 is so arranged as to incorporate a given A ture from the carburetor system of the aforenot'ed copending application.

In order to prevent the auxiliary carburetors from functioning when the engine is cold which would thereby dilute the` fuel-air ratio at a time when a rich mixture was required, a thermostatic device indicated generally at'64 is provided for blocking the ow of vacuum to servo 34 regardless of the actuation of the primary carburetor `10. Any liquid cooled internal combustion engine, such as that shown at 66, with which the subject Icarbureting system is adapted to be employed, includes a cooling system havingv a radiator 68, a coolant passage L 70- leading'from the engine 66 to the radiator'and, aref turn passage 72'le'ading from-"the radiator to th'e engine.

Normally the passage 70 is provided with a thermostat 74 which blocks the ow of engine coolant to the radia- I 3 u lipgw. tor until the engine has reached a given operating temperature. f

In the present device the thermostatic valve mechanism 64 is disposed in conduit 70 between radiator 68T and thermostat'74, AThis particular disposition of the thermo static valve 64 is advantageous because as so oriented the engine coolant cannot act on the valve mechanism until such time as the engine temperature has reached a given operating value. Thisvinsures proper functioning and saves wear on thermostatic mechanism 64. v

The thermostatic valve mechanism 64 includes an venlarged pipe section 78 adapted to be interposed in conduit 70 and having a threaded Vhole 80 formed therethrough within-which a valve body 82 is adapted to be threadably mounted'. Valve body 82 includes a Yportion 84 adapted totproject within and :be exposed to the flow of coolant through pipe section 78. VThis portion of the valve cas'- ing is hollowed out to form a chamber 86, the inner end of which is enclosed by a cover 88 which is clamped in position to seal off the chamber-from the liquid in conduit 70. The casing 82 also includes vacuum inlet and outlet bosses..90 and 92 which are suitably threaded to receive conduits 46 and 48. Inlet boss 90 has a restricted passage. 94 communicating with chamber 86 while outlet boss 92 includes a passage 96 communicating with a chamber 98 formed in the upper portion of the valve casing 82.

.Chamber 98 is likewisesealed oi at one end by a cover 100 and is in communication with chamber 86 through a. plurality of longitudinal passages 102 formed in the common wall 104. A thermostatically expandable cartridge-,106 is disposed in chamber 86 upon cover 88 and includes a stud member 108 adapted to project through a central opening 110 in wall 104. A valve member 112 is iixed to that portion of stud 108 disposed within chamber 98.A

A spring 114 seated upon end cap 100 biases thevalve member 112 downwardly against the force of the thermostatic cartridge 106 so that with the cartridge in its unexpanded or cold position, as shown, ow is prevented between chambers 86 and 9 8. 4Under these conditions conduit 46 communicates with air switch 52 anddelivers vacuum to the thermostatic valve casing chamber 86 but it cannot pass therebeyond as long as the valve 112 remains closed. When thermostat 74 heatszsuicientlyrto permit coolant to pass through conduit 70 the thermostatic cartridge 106 will be warmed and hence. eventually expand, to the position shown in broken line, lifting valve 112 to uncover passages 102 permitting vacuum Vto communicate with outlet boss 92 and hence conduit 48 leading to servo 34.

Thus with the present auxiliarycarburetor control mechanism the air switchSZmust be opened by the actuation of the manual Vcarburetor and the thermostatic valve 112 must be opened by enginetemperature before the auxiliary throttles and 22 may be actuated by servo 34.

1. An internal combustion engine including in combination a cooling vsystem for the engine, a fuel controlsystem comprising a plurality of compounded carburetOrs, each of said carburetors including :a throttle valve, `means for manually operating the throttle valve of one of; said carburetors, means for controlling the actuation ofthe remaining throttle valve whereby said valve may. only be fully opened or fully closed, said controlling means including spring means normallvbiasing said remaining throttle valve in a closed position,a servo for opening said remaining Valve, a device for controlling the actuation, of said servo, aA lost` motion connection between the manual throttle operating means and said device wheref by, said,m anual throttle may besubstantially opened before said servo opens said remaining throttle, and means ;.1- ,;f1:.-= Y. me; 4 -V .mw responsive to the cooling system temperature for controlling the operation of said servo.

2. An internal combustion engine including in combination a cooling system for the engine, a fuel control system comprising a plurality of compounded carburetors, each of said carburetors including a throttle valve, means for manually operating the throttle valve of one of said carburetors, means for controlling the actuation of the remaining throttle valve whereby said valve may only be fully opened or fully closed, said controlling means in-v cluding spring means normally. biasing said remaining throttle valve in a closed position, a uid operated servo for openingsaid remaining valve, airst valve for controlling the ow of tiuid to said servo, a lost motion connection between the manual throttle .operating means and said iirst valve whereby said manual throttle may be substantially opened before said servo opens said remaining throttle, a second valve for controlling the, flownof uid to the servo, and means responsive to the cooling system temperature for controlling the operation of said second valve. y

3. An internal combustion engine including in combination a cooling system for the engine, a fuel control system comprising a plurality of compounded carburetors, each of said carburetors including a throttle valve, means for manually/operating the throttle valve of one of said carburetors, means for controlling ythe actuation of. the remaining throttle valve whereby said valve may only be fullyy opened or fully closed, said controlling means including spring means normally biasing said remaining throttle valve in a closed position, a servo for opening said -remaining valve, a source of substantially constant value vacuum, passage means adapted vto communicate said vacuum with said servo, a rst valve for controlling the ow of vacuum to said servo, a lost motion connection between the manual throttle operating means and said, first `valvewhereby said manual throttle may be substantially opened before said servo opens said remaining throttle, a second valve in series with the first valve, a thermostatic element disposed in the engine cooling system and connected to the second-valve to operate the same in accordance with engine operating temperature.

4. An internal combustion engine including in combination an engine cooling system having a radiator, passage means for circulating a coolant through said engine 'and radiator, a rst temperature responsive valve device in said passage means for blocking the circulation of said coolant until the engine has reached a given operating temperature, a primary carbureting device having a throttle, means for manually actuating Ysaid throttle, an auxiliary carburetor adapted-to supplement the quantity of combusti-ble mixture supplied by said manual carburetor to said engine, said auxiliary carburetor including throttle valve means, a servo for lactuating said auxiliary throttle valve, a source of vacuum, passage means connecting said servo with the vacuum source, a first valve operated by said manual throttle for controlling the ow of vacuum to the servo in accordance with the position of said manual throttle, a second temperature responsive device including a movable valve element for controlling vacuum ilow through the vacuum passage means, aspring member biasing the valve element toward a closed position, and ya temperature responsive element disposed in said coolant passage means for opening the valve element.

References Cited the file of this patent STATES PATENTS n 1,323,456 Decker Dec. 2, 1919 1,330,700 Giesler Feb. 1 0, 1920 2,609,806 Winkler Sept. 9,-1952 2,640,472 Bicknell .June 2, 1953 

